The duo behind Houston rap's biggest hit in years, "Drank in My Cup," has plenty more in store.

"He [Bangz] came in one night and said, 'Man, I need a single,'" says Pyro. "The label had this real pop radio-like song ready for him to release, and he wanted something else. So he just came in and said to give him a hit. We worked all through the night."

Ryu cues up the actual beat from that night.

"It was almost exactly one year ago that we made it," Ryu says.

Amp Designs

Sound M.O.B.'s Pyro (left) and Ryu are trying to grow a brand.

He clicks it on. The swooping WHOOOOMMPs that announce the beat's presence fill the room as rapidly and unforgivably as they do any club or concert venue. All these months later, "Drank in My Cup" still sounds special.

It is the first song of the budding new generation of local rappers to truly gain any national traction, and will eventually be remembered as a flagship moment, for certain.

"When Kirko heard it," reflects Pyro, "something just clicked. I don't know if he had the lyrics ready or what, but he just started going."

He begins singing the hook.

When The Box debuted it in July 2010, the morning crew was so swayed by its immediate appeal that they played it again as soon as it was over. And when it was over the second time, they played it a third. Each time it drew more and more praise.

Everyone knew it was going to be big. And now it is. This spring, "Drank in My Cup" reached the No. 1 spots on Billboard's Rhythmic chart and Billboard's Rap Songs chart. It's the first time a song from a Houston rapper has been that high since Chamillionaire's paradigm-shifting "Ridin' Dirty" in 2006. And it stayed at the top for several weeks, higher than perennial world-beaters Flo Rida, Drake, Rihanna, Young Jeezy, Kanye and more.

So now what?

"That's where we are," says Ryu. "We're lucky that we're in a position now where these record labels are trying to sign us now. They've seen that we can make hits. We want to be real careful, though. We don't want to rush into anything. We want to make it, but it has to be right."